Highly recommend any book by Dr. Lawrence J. Connor (Bee Sex Essentials and Increase Essentials). But, in particular, is a book I'm proud to own and I find a good read and very informative -- Hive Management by Richard Bonney. Hive Management was published in the 90's and is not very up to date with today's challenges of mites, but his chapters on making splits gives good insight to the hobbyist or sideliner on the value of paying attention to thinking ahead. The underlying theme of Bonney's book is what you do today, should shape where you want your hive to be in the next 3-4 months.
"...the most populous colonies ...are provided by queens ...in the year following their birth." Brother Adam